SLK/R171 M271 Engine - strange noises SLK 200K

05-03-2023, 03:10 AM

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stirbex2010

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SLK R171 200k

M271 Engine - strange noises SLK 200K

Hello,

In the last year my car had the following noises 1 or two times a month:

Please refer only to the second 6 and 7 from the video and do not consider the noises from sec 4-5.

I need to mention the following:

the noises usually occur when the car sits longer than 5-6 hours in cold( below 5-10 Celsius) even on a plain surface;
If the car stays in the sun I do not remember hearing the above noises;
the noises usually occur if the car is on an inclined surface with the "nose" up;
the noises occur only at the first start and never come back even if I stop the engine right after I started it;
the oil is always at 5.5-5.4/5.5 liters. The battery is always at 12.4-12.5V.
I tried 5W/40 and 5W/30 all with MB approval for this engine, but no improvement;

Due to this issue described above I decided to change the timing chain, tensioner, slides, and the sprockets(full sprockets not only the teeth) about two weeks ago. The operation was successful and I've made 1500km till now even at max speed(200+km/h) for a couple of minutes, with no check engine, no power loss, and no strange noises while running.
The car continues to do the above noises and for example, in the last week, it happened...3-4 times / 7 days. Is like an improvement...unfortunately in the bad direction.

I thought it could be the:
1. the Bendix from the electromotive - I'm not that sure about it;
2. Oil pump, maybe the oil pressure is low at the beginning and the chain tensioner is not fully stretching the timing chain;
3. vacuum pump - I saw something on some MB forums.
4. Camshaft adjustment screw/valve A2710500171, picture attached

Especially the one from the left side because as I remember the original sprocket from the left side had some nasty wearing there and maybe is something wrong with this "SCREW" or whatever is called...

This is what I've changed to the engine:

I need to mention the fact the car at this moment is in service, the indie decided to keep it there for 2-3 days to listen it in the morning and do some testing.

I really appreciate your response.

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SLK/R171: M271 Engine - strange noises SLK 200K

SLK/R171: M271 Engine - strange noises SLK 200K